摘要
To study the mechanism of ultrasonic vibration assisted forming,the static and vibration assisted compression tests of aluminum 1050 were carried out via a 25 kHz high-frequency ultrasonic vibration device.It is found that vibration reduces the flow resistance and improves the surface topography.The force reduction level is proportional to the ultrasonic vibration amplitude.By using numerical simulation of static and vibration assisted compression tests,the deformation characteristics of material were investigated.Throughout the vibration,the friction between the materials and tools reduces.The stress superposition and friction effects are found to be two major reasons for reducing the force.However,the force reduction because of stress superposition and friction effects is still less than the actual force reduction from the tests,which suggests that softening effect may be one of the other reasons to reduce the force.
为研究超声振动辅助成形的内在机理,设计一套25kHz高频超声振动装置,配合试验机进行1050铝合金静态及振动辅助条件下的压缩试验。实验发现,振动有利于降低材料的流动抗力,同时有助于改善试样表面形貌;成形力的降幅与所施加超声振动的振幅成比例关系。结合有限元数值模拟,研究材料在超声振动辅助压缩条件下的变形特点,发现在振动阶段,试样与模具接触面之间的摩擦条件得以改善。此外,应力叠加和摩擦条件改善是振动阶段成形力降低的两个原因,但两者的降幅总和小于实验中测得的降幅,因此软化效应是成形力降低的另一原因。
基金
Project(51105250)supported by the National Natural Science Foundation of China
Project(P2015-13)supported by the State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology,China
